This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 25 |
| 3 | 57 |
| 4 | 149 |
| 5 | 389 |
| 6 | 1045 |
| 7 | 2837 |
| 8 | 7789 |
| 9 | 21549 |
| 10 | 60005 |
| 11 | 167957 |
| 12 | 472169 |
| 13 | 1332249 |
| 14 | 3770785 |
| 15 | 10701617 |
| 16 | 30442909 |
| 17 | 86779229 |
| 18 | 247817845 |
| 19 | 708837797 |
| 20 | 2030401509 |
| 21 | 5823331109 |
| 22 | 16720830525 |
| 23 | 48060737357 |
| 24 | 138268935049 |
| 25 | 398126270889 |